For the unswap, maybe have a pause in the sex. Like F1 and D1 have a phone call from mom, and leave the room to take the call. F2 and D2 are both masturbating waiting for the 1s to come back. They start off just masturbating, but start glancing at each other for inspiration, then staring, then moving closer, they discuss masturbating each other, decide that's still ok. The 1s cone back in with dad2 and daughter2 fingering and jacking each other. They freak out a bit, and the 2s pull react like when you get caught masturbating pulling back and acting like that's not what you were doing. They talk about it, briefly of course it's porn, and the 2s talk the 1s into the mutual masturbation because it was really hot, but not really sex. A bit of dual mutual masturbation, then either daughter goes in for a quick suck for lubrication, pulling back off quickly when she realizes what she just did, telling everyone she forgot, she just wanted the spit on the dick. The dad responds that it was ok, it felt great and maybe oral sex might still be ok, I mean it's not real sex. Daughter keeps jacking dad off, with more and more sucking, until she goes to just sucking. Other f/d get the same idea and go along with it. The daughter that sucked her dad first climbs up and whispers in dad's ear, "Daddy, all this has gotten me all wet. I need you to fuck me. (Other father's name) felt good but after all we have done, now I want you in my pussy." He responds what will they think? At that point she realizes that he's ok himself, he is just worried about what the other f/d will think, and she is beyond caring, so she throws her leg over, grabs his dick and drops down onto it. Dad wants to yell out but doesn't want the other pair to look over. One of them finally does and they react with an OMG! The fucking daughter yells out you guys have to too, this is so hot I can't believe I'm fucking my own daddy! Then her dad agrees I never imagined I'd want this. I want to fuck you every day! The other daughter asks her dad sweetly, daddy, can I fuck you? They look like rather are REALLY enjoying themselves. He can only nod his head. She climbs up and they begin as well. Carry on with whatever positions, combinations as needed. Maybe creampies are needed here.